A flexible display device is disclosed. In one aspect, the display device includes a display substrate and a display element layer formed over the display substrate and including a matrix of pixels. The display device also includes a thin film encapsulation layer formed over the display substrate and the display element layer so as to protect the display substrate and the display element layer. The display device further includes a window layer formed over the thin film encapsulation layer and a hard coating layer formed over the window layer and having greater hardness than the window layer. The hard coating layer comprises an elastic layer including a plurality of fillers.